New class of compounds showing rattling and related phenomena has been synthesized. (1) The off-center rattling of Ba guests in Ba_8Ga_<16>Sn_<30> enhances the specific heat coefficient and reduces the thermal conductivity. (2) The anomalous phase transition in CeT_2Al_<10> (T=Ru, Os) is an antiferromagnetic order in the partially gapped state. The La counterparts have a three dimensional multiply-connected Fermi surface. (3) The rattling energy of the As-based skutterudites is between those for P-based and Sb-based systems. (4) Among heavy rare-earth filled R_5T_6Sn_<18> (T=Co, Ir), Lu_5Ir_6Sn_<18> shows superconductivity at 2.6 K. (5) The coupling of acoustic phonons and magnetic excitations plays an essential role in the formation of the gap in YbB_<12>.